Jump to content


From Wikipedia, the free encyclopedia

Launch of Saturn AS-104
Mission typeSpacecraft aerodynamics;
micrometeoroid investigation
COSPAR ID1965-039B
SATCAT no.1385
Mission duration8,810 days[1]
Distance travelled3,282,050,195 kilometers (2.039371443×109 mi)
Orbits completed~79,790
Spacecraft properties
SpacecraftApollo BP-26
Pegasus 2
Launch mass1,451.5 kilograms (3,200 lb)
Start of mission
Launch dateMay 25, 1965, 07:35:01 (1965-05-25UTC07:35:01Z) UTC
RocketSaturn I SA-8
Launch siteCape Kennedy LC-37B
End of mission
Decay dateJuly 8, 1989 (1989-07-09)[1]
Orbital parameters
Reference systemGeocentric
RegimeLow Earth orbit
Perigee altitude511 kilometers (318 mi)
Apogee altitude739 kilometers (459 mi)
Inclination31.7 degrees
Period97.2 minutes
Epoch4 July 1965[2]
← AS-103
AS-105 →

AS-104 was the fourth orbital test of a boilerplate Apollo spacecraft, and the second flight of the Pegasus micrometeoroid detection satellite. It was launched by SA-8, the ninth Saturn I carrier rocket.


The primary mission objective was to demonstrate the launch vehicle's iterative guidance mode and to evaluate system accuracy. The launch trajectory was similar to that of mission AS-103.

The Saturn launch vehicle SA-8 and payload were similar to those of mission AS-103, except that a single reaction control engine assembly was mounted on the boilerplate service module (BP-26). The assembly was instrumented to acquire additional data on launch environment temperatures. This assembly also differed from the one on the AS-101 mission in that two of the four engines were of a prototype configuration instead of all engines being simulated.


This was the first nighttime launch in the Saturn I series. A built-in 35 minute hold was used to ensure that launch time coincided with the opening of the launch window.

AS-104 was launched from Cape Kennedy Launch Complex 37B at 2:35:01 a.m. EST (07:35:01 GMT) on May 25, 1965.[3] The launch was normal and the payload was inserted into orbit approximately 10.6 minutes after lift-off. The total mass placed in orbit, including the spacecraft, Pegasus B, adapter, instrument unit, and S-IV stage, was 34,113 pounds (15,473 kg). The perigee and apogee were 314.0 and 464.1 miles (505 and 747 km), respectively; the orbital inclination was 31.78'. The 1397 kilogram (3080-pound) Pegasus 2 satellite was also carried to orbit by SA-8, being stowed inside the boilerplate's service module, and remaining attached to the S-IV stage.

The actual trajectory was close to the one predicted, and the spacecraft was separated 806 seconds after lift-off. Several minor malfunctions occurred in the S-I stage propulsion system; however, all mission objectives were achieved.[4][5]


  1. ^ a b "Apollo Model 4". n2yo.com. Retrieved February 3, 2023.
  2. ^ McDowell, Jonathan. "Satellite Catalog". Jonathan's Space Page. Retrieved October 31, 2013.
  3. ^ "May 1965". Saturn Illustrated Chronology - Part 6 January 1965 through December 1965. NASA. Retrieved February 3, 2023.
  4. ^ Pack, P. B.; Solmon, G.W. (May 17, 1965). "SA-8 operational trajectory". Retrieved February 3, 2023.
  5. ^ Weichel, H. J. (August 2, 1965). "SA-8 flight test data report". NASA. Retrieved February 3, 2023.

External links[edit]

Public Domain This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration.